raw silk fabric
綃 centers on raw silk fabric, the unrefined material before it is processed into finished silk goods.
綃 combines the thread radical 糸 with the phonetic component 肖, forming a character for a type of silk fabric. The exact historical development is uncertain, but the structure is a typical phono-semantic compound.
The thread radical 糸 on the left hints at silk, and the right side 肖 looks like a small, raw cocoon. Picture raw silk threads being drawn from a cocoon: 綃 is raw silk fabric.
For ショウ, imagine a raw silk fabric so fine it is used for a showy garment: show -> ショウ, and the fabric is still raw and unprocessed.